Sweet graphs. I'm a process/automation engineer by day, so I'm gonna dig in here.
1. I'm assuming this is just a test? During an actual fermentation/lagering, chilling the beer 20F in 4 hours is way too fast. Go for 1-2F over the course of a day.
2. You'll never drop your fermentor temperature to the temperature of the glycol. This is why the temp flatlined ~ 40F when your glycol was 35F - the temperature difference wasn't large enough to transfer heat.
Think about cooling your wort on brewday. The wort temp cools to several degrees above the cooling water temp. Instead of raising the glycol temp, just recirc when cooling is needed.
3. What is your glycol/water mix? The more water, the better the heat transfer. 50/50 is usually a good blend of freeze protection and heat transfer. I would expect that 35-40F would be a good setpoint for primary fermentation, and 25F-30F would be good for maintaining lager temps. Depends on coil dims, insulation, ambient temp, etc.
4. Have you checked calibration on your temperature sensors? If you don't have a calibration thermometer, check them against a few of your brewday thermometers.
Can you post more pics of this fermentor, the chiller, and the controls? I would love to see it!